DIVERSITY  OF 


NQN  CIRCULATING 

CHECK  FOR  UNBOUND 
CIRCULATING  COPY 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  259 


THE   CULTIVATION   OF   CORN 

Weed  Control  vs.  Moisture  Conservation 

BY  D.  C.  WIMER  AND  M.  B.  HARLAND 


URBANA,  ILLINOIS,  MARCH,  1925 


SUMMARY 

The  principal  object  and  greatest  value  of  corn  cultivation 
on  Brown  Silt  Loam  is  the  destruction  of  weeds.  Weedy  corn 
probably  suffers  more  from  a  lack  of  nutrients  than  from  a 
moisture  deficiency  in  this  climate.  Since  cultivation  is  the 
only  practical  method  of  controlling  weeds,  the  depth  and 
frequency  of  corn  cultivation  should  be  determined  by  their 
growth.  The  growth  of  weeds  should  be  prevented  in  so  far 
as  possible  by  shallow  rather  than  by  deep  cultivation. 

Deep  cultivation  of  corn  may  result  in  root  injury  and 
decreased  yields  in  comparison  with  shallow  cultivation.  The 
effect  of  excessive  and  deep  cultivation  seems  comparable  to 
that  of  actual  root  pruning.  Proper  cultivation  should  kill 
the  weeds  with  minimum  injury  to  the  corn  roots;  obviously, 
this  is  more  easily  accomplished  when  the  weeds  are  small. 

The  need  for  cultivation  seems  to  be  no  greater  in  dry 
than  in  wet  years;  it  may,  in  fact,  be  less.  However,  on 
heavy  soils  which  check  badly,  cultivation  may  be  necessary 
in  order  to  fill  the  large  cracks  and  thus  stop  the  direct  loss 
of  moisture  from  the  deeper  strata. 

The  data  and  brief  discussions  presented  in  this  bulletin 
are  intended  to  be  of  assistance  in  developing  the  principles 
underlying  the  successful  cultivation  of  corn  and  are  not  in- 
tended as  recommendations  of  specific  methods  or  particu- 
lar implements. 


(This  Bulletin  is  a  revision  of  No.  181.  Soil  Moist- 
ure and  Tillage  for  Corn,  issued  in  1915.  See  note, 
page  196.) 


THE   CULTIVATION   OF   CORN 

Weed  Control  vs.  Moisture  Conservation 

By  D.  C.  WIMER,  Assistant  Chief  in  Soil  Physics,  and  M.  B.  HARLAND,  First 
Assistant  in  Soil  Physics 

The  cultivation  of  corn  is  clearly  for  the  purpose  of  making  a  more 
satisfactory  crop  yield  possible.  The  specific  reasons  why  cultivation 
helps  to  achieve  this  result  are  not  so  obvious.  Several  explanations 
have  been  offered;  one,  a  common  assumption,  has  been  that  the  mulch 
formed  by  cultivating  the  soil  results  in  the  conservation  of  moisture. 
There  seems  to  be  no  evidence  to  justify  this  conclusion;  instead,  it  is 
now  generally  recognized  that  the  drier  the  season,  the  less  need  for 
cultivation.  Even  in  arid  and  semiarid  regions  where  the  evaporation 
rate  is  high,  cultivation  apparently  results  in  little  or  no  conservation  of 
moisture.  The  killing  of  weeds,  however,  appears  to  have  been  proved 
the  most  important  object  of  cultivation;  except  on  very  heavy  soils 
which  check  badly,  it  seems  that  cultivation  ordinarily  is  necessary  only 
for  the  control  of  weed  growth. 

A  dry  crust  is  probably  just  as  effective  in  checking  the  movement  of 
water  vapor  from  the  deeper  layers  of  moist  soil  to  the  open  air  as  is  a 
dry,  granular  mulch.  If  the  conditions  are  such  that  this  dry  top  layer 
forms  promptly,  then  it  is  clear  that  cultivation  is  not  needed  as  an  aid 
to  its  formation.  If  it  does  not  form  promptly,  then  cultivation  will 
assist  in  its  formation  by  increasing  temporarily  the  rate  of  evaporation. 
Fig.  1  perhaps  gives  a  clearer  idea  of  the  way  in  which  a  dry  top  layer 
of  soil  affects  evaporation  than  can  be  given  by  discussion. 

Under  field  conditions,  the  upward  movement  of  capillary  water  is 
very  slow  as  soon  as  the  saturated  condition  of  the  soil  in  early  spring 
is  past.  A  dry  top  layer  then  forms  readily  because  the  amount  of 
water  evaporated  from  the  surface  exceeds  the  amount  brought  up  by 
capillary  rise,  and  loss  by  evaporation  is  thus  decreased. 

From  the  above  it  would  seem  that  conservation  of  moisture  is  not 
a  reason  for  cultivating  corn  except  possibly  in  case  of  soils  which  crack 
badly.  This  conclusion  is  strengthened  by  the  fact  that  early  in  the 
growth  period  the  corn  roots  become  so  completely  distributed  between 
the  rows  that  they  intercept  any  moisture  which  may  be  brought  up  by 
capillary  action.  Thus  there  is  little  chance  of  the  moisture  reaching  the 
surface  and  evaporating. 

SHALLOW  CULTIVATION  PREFERABLE 

Cultivation  should  always  be  as  shallow  as  possible,  altho  deeper 
stirring  is  less  harmful  at  the  first  cultivation  than  later.  For  the  highest 
yields,  cultivation  should  never  be  deep  enough  to  injure  the  roots,  for 
such  injury  is  likely  to  retard  the  development  of  the  corn  plant. 

175 


176 


BULLETIN  No.  259 


[March, 


It  must  be  remembered  too,  that  the  plowed  stratum  is  the  richest 
in  available  plant  nutrients,  and  that  it  is  far  more  valuable  as  a  feeding 
ground  for  the  corn  roots  than  it  is  as  a  dry  layer  of  soil  functioning 
as  a  mulch. 

That  good  yields  of  corn  cannot  be  produced  in  fields  where  weeds 
are  allowed  to  grow  unmolested  is  clearly  shown  by  results  of  experi- 


EVAPORATION  RATE  DETERMINED  BY 
KATE  OF  CAPILLARY  RISE. 

EVAPORATION  KATE  DCTEKUWED  BY  RATt  OF 
PAS^ACC.  OF  WATER  VAPOK  THRU  MYSO/L 

* 

D, 

a 

" 

ryCT»tX't^rT 

Esoporotmq  svrfoct  <j 

1 

A 

B 

C 

FftE 

f  CA 

°/L 

if 

"A 

iSt 

n 

E 

/At 

'OR 

ATI 

SU< 

l» 

C£ 

FIG.  1. — SHOWING  How  THE  CONDITION   OF  THE  TOP  SOIL  AFFECTS  THE 
EVAPORATION  OF  SOIL  MOISTURE 

So  long  as  the  soil  is  moist  entirely  to  the  surface  (A),  evaporation  is 
free  to  go  on;  but  just  as  soon  as  a  dry  layer  forms  (B  and  C),  the 
evaporating  surface  is  lowered  to  the  bottom  of  the  dry  soil  and  any 
further  loss  must  take  place  by  movement  of  the  water  in  the  form  of 
vapor  thru  the  dry  soil.  Since  the  movement  of  water  in  this  way  is 
exceedingly  slow,  the  loss  of  soil  moisture  is  greatly  lessened. 


ments  at  this  Station  and  by  the  experience  of  farmers.  For  instance, 
with  the  same  preparation  of  seed  bed,  only  7.4  bushels  of  corn  per  acre 
were  produced  as  a  nine-year  average  where  weeds  were  allowed  to 
grow,  while  48.9  bushels  were  obtained  where  the  weeds  were  kept 
down  without  any  cultivation.  Keeping  the  weeds  down  was  apparently 
responsible  for  an  increase  of  41.5  bushels  yearly.  This  is  easy  to  under- 
stand when  we  realize  that  weeds  deprive  the  corn  plant  of  moisture, 
light,  and  nutrients,  all  of  which  are  necessary  for  the  growth  of  the 
plant  and  seed.  Of  these  factors,  however,  the  lack  of  plant  nutrients 
probably  makes  the  greatest  difference. 

On  another  plot  weeds  were  allowed  to  grow,  but  the  plot  was  irri- 
gated so  that  the  corn  was  not  deprived  of  moisture,  yet  the  increase 
from  irrigation  as  a  five-year  average  was  only  2.5  bushels  an  acre. 


1925]  THE  CULTIVATION  OF  CORN  177 

Weeds  are  much  better  foragers  than  are  most  cultivated  crops;  as 
has  well  been  said,  "It  would  be  just  as  reasonable  to  expect  a  lamb  to 
thrive  with  a  bunch  of  hogs  as  to  expect  corn  to  compete  with  weeds." 

EARLY  EXPERIMENTS  AT  URBANA 

Morrow  and  Hunt  began  some  experiments  in  1888  to  determine 
the  value  of  cultivation  and  its  best  depth  and  frequency;  also  the  effect 
of  root  pruning.  These  experiments  were  continued  up  to  and  including 
1893  by  Gardner,  who  concluded  that  "there  seems  to  be  no  advantage 
in  cultivating  more  frequently  than  is  necessary  to  destroy  weeds  and 
keep  the  ground  moderately  porous;  that  shallow  cultivation  has  never 
failed  to  produce  an  increase  in  yield  over  that  of  deep  cultivation";  and 
that  "root  pruning  has  never  failed  to  reduce  the  yield  in  a  marked 
degree."  Table  1,  reprinted  from  Bulletin  181  of  this  Station,  gives  a 
partial  summary  of  the  results  obtained  in  these  early  cultivation  experi- 
ments, and  Table  2  shows  the  rainfall  by  months  during  the  time  the 
experiments  were  in  progress,  with  the  exception  of  the  year  1888,  for 
which  the  record  is  not  complete. 

Where  the  weeds  were  kept  down  by  scraping  with  a  hoe  without 
producing  a  mulch,  the  yield  as  a  six-year  average  was  96.9  percent  of 
that  for  ordinary,  shallow  cultivation — a  difference  of  2.1  bushels  an 
acre  in  favor  of  cultivation.  Deep  cultivation  practiced  four  or  five  times 
also  gave  a  96.9-percent  yield,  or  2.1  bushels  less  than  shallow  cultiva- 
tion. As  a  five-year  average,  shallow  cultivation  practiced  twelve  to 
fourteen  times  during  the  season  gave  a  103.6-percent  yield,  or  an 
increase  of  2.5  bushels  an  acre  over  ordinary  shallow  cultivation,  while 
deep  cultivation  the  same  number  of  times  gave  a  91.7-percent  yield,  or 
a  decrease  of  5.8  bushels  an  acre.  Compared  with  twelve  to  fourteen 
shallow  cultivations,  deep  cultivation  practiced  twelve  to  fourteen  times 
resulted  in  a  decrease  of  8.3  bushels  an  acre. 

These  decreased  yields  from  deep  cultivation  seem  comparable  to 
the  results  secured  from  actual  root  pruning  in  another  portion  of  the 
same  experiment.  A  frame  twelve  inches  square  was  placed  over  the  hill 
and  a  knife  run  around  the  outside  to  a  depth  of  four  inches,  thus  cut- 
ting the  roots  to  that  depth.  Where  shallow  cultivation  was  practiced, 
this  pruning  resulted  in  a  decrease  of  13.2  bushels  an  acre  as  an  average 
of  six  years,  but  where  the  weeds  were  removed  by  scraping  with  a  hoe 
instead  of  by  shallow  cultivation,  the  yield  was  diminished  16.9  bushels 
an  acre  as  an  average  of  four  years. 


178 


BULLETIN  No.  259 


[March, 


>  oo 
<     Z 


4  * 


Kind  o 


Efc 


so 


OS  OO 

vo  O 


co  so       Os  so 


oo        .— i  — i 


Os  t^- 

oo  O 


i  O        —  < 

i  so      r^ 


~        so  Ol 


O  O 
Os  Os 


.§5 


c*  o  z.  & 

"-   ^  g<  3 

~r  I  C    u 

fe  ^  3D. 


88 


J3    o 

•£-0 

'^   I 


- 


3    u 
U§ 

c  2 
3  a 

tn    co 


P 

to 


* 


o» 

co  t:  -o 
-  o-TJ 


3 

w 

r~-  oo  co  vor^ 
oscsr--o  ts 

g 

3 

vo  -H  so  Os  CS 
CO  CO  CS  CO  co 

CO 
CO 

cJ 

(S  vo  CO  CS  OS 

oo  O  vo  so  O 

es 

CN 

Q 

1—  1            1—  1  I—  <  »-! 

*"* 

>- 

OO  CO  OO  vo  OO 

CS  so  vo  os  Os 

00 

oo 

Z 

—  —  ,r   ~  ~  . 

CO 

*j 

CS  vo  OS  CO  •* 

.•*  co  cs  os  ^ 

5 

0 

t-i  es  i—  i      ^i 

1—1 

o. 

•*  Os  -*CO  tN 

r-~  T-<  rf  os  so 

00 

r^ 

u 

C/3 

CS»^             CO 

"^ 

bb 

O  co  so  co  so 

so  Os  oo  Tt<  O 

oo 

VO 

< 

»-H  tN  IN 

*""* 

X 

-H   CO   ^H   O   OS 

OO  OO  Tf  vo  vo 

CO 

so 

i—  > 

VOCS  ~  C4 

cs 

u 

§O  oo  so  vo 
oo  O  co  vo 

so 

3 
I—  » 

OO  CO  «S  vo  i-i 

•* 

X 

CIS 

CS  so  Os  so  co 
VO  VO  OO  OO  OO 

CO 

VO 

Oj 

o 

s 

VOCO         1^  Tf< 

•* 

Si 

4-1 
o 

c 

^H   -H   T}<  VO   OO 

VO  —  i  vo  Tf  so 

oo 
•* 

G 

d> 
o 

C 

< 

•<f  cosor^ 

•<*< 

V 

'v 

c 
• 

^  O  vo  Os  O 
so  t^-  vo  vo  CS 

CO 

r^ 

jy 

"3. 

s 

^  tN  COfS  CO 

cs 

0 
u 

.s 

^i 

oo  r-  o  •<*•  oo 
O  OO  SO  so  rf 

co 
r^ 

oo 
oo 
oo 

fa 

(N  "-c  CSCS  •* 

01 

1—  1 

•5 

c 

oo  so  Os  Os  vo 

Os 

-o 

8 

i—  » 

^H  VO                     r« 

rt 

" 

4) 

Os  o  —  '  o<  co 

00  OS  OS  OS  OS 

oo  oo  oo  oo  oo 

t4 

u 

H 

< 

1925]  THE  CULTIVATION  OF  CORN  179 

LATER  EXPERIMENTS  AT  URBANA 

The  results  obtained  by  Morrow  and  Hunt  were  contrary  to  popu- 
lar belief  and  seemed  so  remarkable  that  in  1906  and  1907  a  series  of 
experiments  was  begun  to  test  them  and  at  the  same  time  to  obtain 
information  on  some  other  features  such  as  the  damage  resulting  from 
allowing  weeds  to  grow  and  the  value  of  seed-bed  preparation,  irriga- 
tion, and  fertilizer  treatment. 

The  results  of  these  experiments,  as  given  in  Table  3,  represent  the 
averages  of  first  and  second-year  corn;  the  individual  yields  are  reported 
in  Table  4  for  the  convenience  of  those  who  may  care  to  make  a  more 
thoro  study  of  the  data.    Table  5  gives  the  rainfall  during  the  time, 
covered  by  the  experiments. 

The  soil  on  which  these  experiments  were  conducted  is  Brown  Silt 
Loam,  an  upland  prairie  soil  formed  from  loess  overlying  the  drift  of 
the  early  Wisconsin  glaciation.  This  soil  is  fairly  representative  of  the 
gently  undulating  areas  of  the  corn  belt  in  Illinois.  The  field  had  been 
under  cultivation  for  fifty  years  or  more,  but  during  that  time  no  ferti- 
lizer had  been  applied,  with  the  possible  exception  of  barnyard  manure. 

A  four-year  rotation  of  corn,  corn,  oats,  and  clover  was  practiced. 
The  cornstalks  and  both  crops  of  clover  were  removed.  In  1912  and 
1914  soybeans  were  grown  because  of  the  failure  of  clover.  The  cultivat- 
ing was  done  with  the  three-shovel  cultivator  till  1912,  and  after  that 
the  surface  cultivator  was  used. 

While  the  total  rainfall  of  1911  and  1913  appears  to  be  approxi- 
mately normal,  yet  in  both  these  years  there  were  dry  periods  during 
the  time  when  corn  should  have  been  making  its  greatest  growth  and 
needed  a  large  supply  oi  moisture.  It  will  be  noted  that  in  1911  during 
June  only  .82  inch  of  rain  fell,  and  during  July  .62  inch;  while  in  1913 
in  May  only  .56  inch  fell;  in  June,  1.67  inches;  in  July,  1.52;  and  in 
August  1.44  inches.  The  year  1913  was  the  driest  during  the  growing 
time  for  corn  since  the  rainfall  record  has  been  kept  at  the  University. 

Table  6  gives  the  amount  of  water  applied  to  the  irrigated  plots  for 
each  year  of  the  experiment,  and  also  the  rainfall  from  April  1  to 
August  31. 

It  will  be  seen  that  the  largest  amount  of  water,  16.91  inches,  was 
applied  during  1911,  and  the  next  largest,  12.85  inches,  in  1913.  The 
water  was  applied  by  the  furrow  method  of  irrigation,  individual  appli- 
cations being  approximately  equal  to  one  inch  of  rainfall.  After  it  was 
absorbed  and  the  soil  had  become  sufficiently  dry,  the  furrows  were 
partly  filled  with  loose  soil  to  prevent  an  excessive  loss  by  evaporation. 
The  yields  for  1913  were  diminished  by  the  extreme  heat  during  the 
time  when  pollination  was  taking  place.  A  storm  on  July  16,  1914, 
damaged  the  corn  on  all  plots  to  some  extent,  but  particularly  where 
the  growth  was  rank,  as  on  the  fertilized  and  irrigated  plots. 


180 


BULLETIN  No.  259 


[March, 


S5     S 
O     O 

<  "o. 

<  ° 

ll 


x 
W 


10 

CO 

<0 

00 

o 

CO 

vo 

O 

-*• 

JM 

§ 

2 

vg 

CM 

8 

ON 

>d 

jo 

o 

^H 

»"• 

*—* 

"H. 

0-, 

>: 

f 

^. 

VO 

o 

O 

QO 

"o 

ot« 

d 

00 

00 

o 

id 

S 

to 

^ 

a 

,; 

^ 

CO 

ON 

„, 

o 

ON 

fce 

< 

ct  « 

00 

2 

Isl 

8 

to 

'•5 

^- 

^* 

n! 

J 

CO 

•* 

w 

•* 

0 

00 

00 

C 

>. 

^ON"^ 

oo 

* 

(^ 

d 

^ 

vd 

ON 

0 

to 

•* 

to 

VO 

T3 

£H 

. 

•  ON  Tj1 

o 

^ 

O 

oo 

to 

00 

S 

3 

1 

sli 

vd 

oo 

ts! 

3 

to 

ON 
vo 

3 

"3 

^  , 

CM 

ON 

•* 

m 

CM 

8 

00 

>>  « 

to 

00 

I>I 

'^ 

d 

CO 

*^ 

CO 

"* 

* 

to 

CU 

o 

to 

ON 

CN 

0 

ON 

O 

CO 

ON 

^ 

ON 

•W 

CM 

OO 

to 

vd 

0 

M 

c3 

S 

Q 

VO 

*^ 

** 

t*«* 

^ 

>, 

g 

S 

«* 

to 

ON 

„ 

^. 

M 

CM 

^H 

ti 

.S 

ON 

00 

ON 

a 

d 

3 

S 

vd 

c< 
*-> 

& 

ON 

vd 

ON 

o 

CM' 

o\ 

1 

d 

»s 

to 

a 

^ 

"H 

CO 

fj 

• 

p 

CM 

1 

"! 

^ 

to 

1 

1 

o 

U 

«• 

h 

ON 

58 

tC 

** 

s 

'•S 

3 

ON 

'S 

^1 

CJ 

_ 

.0 

00 

Ov 

(^ 

in 

0 

CO 

CX. 

a1* 

~3 

ON 

to 

ON 

^ 

•* 

to 

(^ 

2^ 

CM 

rt 

to 

""* 

^ 

_^ 

O 

-c 

VO 

"* 

r^ 

CM 

CO 

** 

J  § 

0 

CN 

CO 

o 

i/) 

d 

00 

u 

3     3 

CO 

•* 

^* 

to 

.S 

P_,pQ 

T3 

ON 

VO 

K 

t^ 

•* 

o 

ON 

to 

o     D 

U2 

T3 

d, 

ON 

oo 

d 

O 

*-~ 

o 

CM 

C 

•4-*     *• 

CM 

^H 

CM 

to 

V* 

•# 

£  ^ 

00 

o 

O 

o 

O 

CM 

00 

«f 

2"fl 

O 

§ 

to 

CO 

vd 

if) 

OO 

oo 

^ 

^'^      CH 

1^ 

CM 

CO 

r-i 

CM 

CM 

C- 

c 

w    rt 

T3    .9 

CO 

fc 

CM 

0 

o 

VO 

OO 

CM 

B 

O 

£ 

g 

00 

i 

o 

ON 

$ 

0 

c 

'^"S 

S 

tr. 

c.  . 

.i    ; 

• 

• 

•»  ; 

o 

^  £ 

r2 

'S. 
2 

V      . 

: 

.«    ' 

J 

J 

J      '• 

ctf 

7n 

J 

£ 

•§  ; 

P 

o    ! 

« 

CO 

CO      • 

00 

-fl    to 

"   ; 

EC 

fc   ; 

a 

c 

c    '. 

^^ 

^    n! 

_^ 

.0 

^      ; 

o 

o   • 

0 

_o 

O     . 

c 

S^-rl 

c 

z 

c  : 
_o    . 

"2 

-a   • 

ri 

^ 

> 

«     • 

OJ 

QJ     D 

.'£ 

o 

"O 

5 

•f   • 

15 

!5   • 

~ 

•g    to 

S 

4-1 

a 

Jl 

"5   • 

"«5 

_o    ; 

IW  CU 

3 

u 

& 

3    ; 
S    : 

M 

-tJ~ 

p 

~? 

•S  • 

^ 

;2 

_o  : 

.5 

£  ^* 

^ 

w 

-o 

O   (J 
C  o 

i 

1 

^3 

3  : 

c 

o 

H 

c 

1 

iS 
"O 

.— 
"S^s 

•g 

•a    ! 

-rf 

|" 

•a"  i 

> 
'5> 

33 

^, 

h 

V 

_j> 

*4-) 

°3 

rt'5 

o.  * 
S  "> 
o.S 

•8- 

M 

o,  : 

a  • 

c_ 

t_ 
B> 
•o 

a 

o. 
•a 

S-iJ 

"    M 

1^:= 

^  -O 

J 

" 

^  S 

Js 

^   '• 

-S 

J 

^  ,4 

'B 

"rt  "B 

O 

"5  o 

•o  ^ 

"3 

-o  : 

•a 

•g-o 

•a-o 

1 

g  i 

| 

Not  plowe 
with  h 

Plowed,  si 
down  1 

Plowed,  st 

it 

o 
CL 

Plowed,  s< 

Plowed,  si 
irriga 

Plowed,  se 
irrigati 

1 

<u  ~ 
w   ° 

"o 
2 

j* 

I 

M 

- 

CM 

tfl 

z 

* 

to 

to 

O 
60 

19251 


THE  CULTIVATION  OF  CORN 


181 


5 


CO 

Z 
o 

=: 

« 
% 

O 


II 


Os- 

to  so 

•*o 

Oto 

oo 

•*so 

to  Os 

o 

to  " 

ooS 

000 

OS-* 

tO-H 

88 

to  to 

tOC 

E 

0<s 

•*  to 

OOO 

oo 

—  tv. 

tv^. 

&s 

oo  a 

00  OO 

Soo 
0 

00 

88 

•-JOO 
C-4O 

to  to 

5; 

. 

to  to 

tv-, 

rv,o 

00 

«ST(< 

to 

ok  * 

KS 

IV  OO 

OS-* 

88 

Ss 

Jo 

^ 

•i  — 

00  OO 

00  -H 

to  so 

Os  00 

0- 

OHO 

SOOs 

to 

«2—  i 

S8 

£S 

OssO 

2|  to 

00  tv 

TT-* 

S^5 

to  to 

tvsO 

.« 

00 

"o  o 

£S 

!o$ 

Os-* 

^Q! 

\Q  \£) 

tsso 

tv  SO 

1 

0*. 

so  to 

OOO 

tvOS 

^>o 

-* 

0 

« 

SJo 

r-i  to 
to-* 

oo  so 

3* 

to  to 

10-* 

Os 
SO 

.0 

so  to 

-00 

totv 

OOs 

SO-* 

SO—I 

OsO 

2 

ss 

££! 

*°s 

tooo 

tooo 

s:s 

ooto 

IV  SO 

* 

OstN 

^-j. 

Ostv. 

IV  — 

0-f 

r^**^ 

00-* 

2 

*™ 

£'3 

ooto 

so-* 

•—Os 

ss 

Osts 

1 

-*to 

SO  SO 

00  OS 

oo  os 

to  to 

SOOO 

too 

SOOO 

to  so 

tv* 
Iv'tO 

to  •* 

rl 

to-. 

~0 

so  to 

-.0 

tvtv 

SO  Os 

^•tv 

^ 

OC-* 

SOOO 

toOs 

SOtv 

to  so 
sosO 

losS 

too 

Cs  ON 

O-H 

Olv. 

to  to 

so  Os 

so  to 

00  CM 

TJ-CM 

r\ 

Set; 

OsO 

rt 

ts 

OOO 

—IOO 
SO-* 

SOOO 

3 

—  -H 

SO  SO 

OOO 

.  . 

^•0 

-H-* 

SOO 

> 

ss 

S3 

o 

;  ; 

^§ 

to? 

sg 

1 

2> 

to  Os 

Os  so 

tO~H 

tv« 

to  IV. 

Os^ 

Js 

•H 

23 

SO  to 

^.tv 

CN  to 

3S 

•* 

o 

c 

5 

*so 

10  OO 

ooto 

ooto 

0-0 

tsrf 

*""" 

I 

§ 

S^ 

tots 

<s 

OO*—  « 

??rt; 

OS  00 

\0 

I 

00  tv 

oo  ts 

oo 

0<N 

SOO 

tvtv 

o 

g 

3S 

to  to 

oo 

so  to 

SO  to 

=  S 

OH 

Q 

T3 

4 

c 

• 

• 
| 

I 

ivnted,  weeds  kept  down  1 
iihoe  2 

jrepared,  no  cultivation,  1 
i  by  scraping  with  hoe  2 

epared,  weeds  allowed  to  1 
2 

•epared,  weeds  allowed  to  1 
2 

repared,  shallow  cultiva-  1 
2 

repared,  shallow  cultiva-  1 
gated  2 

repared,  shallow  cultiva-  1 
fated,  fertilized  2 

O. 

— 
a 

o 

ns 

1 

^j 

4 

Not  plowed  or  cult 
by  scraping  wit 

Plowed,  seed  bed 
weeds  kept  dow 

Plowed,  seed  bed  p 
grow  

4J*s 

£ 

Plowed,  seed  bed  p 
tion  3  times  

"S.I 

V  '  ~ 

-o  c 
C 

Plowed,  seed  bed  p 
tion  3  times,  irri 

0 

'I 

rt 

3 

1: 

1 

rt 

ts 

to 

Z 

<• 

10 

SO 

182 


BULLETIN  No.  259 


[.March, 


vor^oovO'-'OTj<r--oo 

COOO^CSCOOOOOCNCO 


«-<      es  —i  n  cs  •<*<  cs 


S! 

D 


ON  ON  ON 


^  C?N  ON  OS  Os  O\ 


VO 

oo  t^ 

oo  O 

2 

CN 

i 

°S 

CO 

OO  vo 

CO  OO 

ot 

f^  CN 

CN 

ON  00 
CO  CN 

ON 

JV.VO 

_ 

oo  ON 

ON 

O  vo 

0 

ON  r~^ 

ON 

vo'oo 

1 

ON  00 
vo  00 

00 

g 

oo  vo 
ON  vo 

1 

a! 

<J   C 
C'" 
'"  OO 

o  vq 

gS 

S-g 

s  s 

3  "ft 
bO  ft 
3    « 

22 

«    * 

q>    O 
T3  "O 
T3TJ 

re   re 

ft  « 
—  o 

Amount 
'Amount 

II 

1925]  THE  CULTIVATION  OF  CORN  183 

CULTIVATION  NEEDS  No  GREATER  IN  DRY  YEARS 

The  statement  has  frequently  been  made  that  the  drier  the  season, 
the  greater  the  need  of  cultivation.  However,  this  has  never  been  proved 
by  experimental  results  where  the  yield  of  the  crop  produced  has  been 
taken  as  the  standard  of  measurement.  There  is,  on  the  other  hand, 


AVERAGE  RAINFALL 


AVERAGE  RAINFALL 


1907            1908             1909             1910  1911  1912  1913  1914  1915 
SECOND  YEAR  CORN 


AVERAGE  RAINFALL 


I 


1907  1906  1909  13/0  1911  19/2  1913 

AVERAGE.  OF  FIRST  AND  SECOND  YEAR  CORN 

FIG.  2. — THE  NECESSITY  OF  CULTIVATION  AS  INFLUENCED  BY  RAINFALL 

This  diagram  constructed  from  the  data  given  in  Tables  3,  4,  and  6,  shows 
the  comparative  yields  on  the  "scraped"  and  "cultivated"  plots  in  relation  to  the 
total  rainfall  from  April  1  to  August  31.  There  seems  to  be  little  or  no  evidence 
of  greater  cultivation  need  in  seasons  of  limited  rainfall. 


184 


BULLETIN  No.  259 


[March, 


some  evidence  which  tends  to  discredit,  if  not  to  disprove,  this  teaching. 
It  may  be  noted  from  the  accompanying  diagram  (Fig.  2)  that  dur- 
ing the  four  years  when  the  rainfall  was  below  the  nine-year  average, 
cultivation    gave    an    increased    yield    but    once.    This    increase — 14.8 


FIG.  3. — DECREASED  GROWTH   RESULTED  WHERE  PLOWING  AND  PREPARATION  OF  SEED 

BED  WERE  OMITTED 

On  this  plot  (No.  1,  photographed  in  1911)  the  weeds  were  kept  down  by  scraping 
with  a  hoe,  but  the  ground  had  not  been  plowed  nor  a  seed  bed  prepared.  Compare 
with  Fig.  4. 


bushels  an  acre  in  the  first-year  corn  in  1910 — is  insignificant  when  com- 
pared with  the  total  decrease  in  the  first-  and  second-year  corn  in 
1910,  11  and  1913,  14,  which  amounted  to  58.8  bushels.  The  net  de- 
crease as  a  result  of  cultivation  on  the  two  plots  during  the  four  years 
when  the  rainfall  was  deficient  in  the  growing  period,  was  44  bushels  an 
acre.  An  average  decrease  of  5.5  bushels  of  corn  to  an  acre  would 
hardly  warrant  any  recommendations  for  more  cultivation  in  dry 
seasons. 

TREATMENT  OF  PLOTS 

Plot  1  (Fig.  3)  was  plowed  for  the  oats  crop  only;  that  is,  but  once 
in  each  rotation.  The  vegetation,  such  as  clover  or  corn  stubs,  was 
removed  and  the  corn  planted  with  a  hoe.  The  weeds  were  kept  down 


1925] 


THE  CULTIVATION  OF  CORN 


185 


by  scraping  with  a  sharp  hoe  so  as  to  produce  practically  no  mulch,  and 
this  was  done  only  as  often  as  necessary  to  kill  the  young  weeds. 

Plot  2  (Fig.  4)  was  plowed  in  the  spring  about  6  inches  deep  for 
corn;  a  good  seed  bed  was  prepared  before  planting  the  corn,  but  no 


FIG.  4. — BETTER  GROWTH  RESULTED  FROM  PLOWING  AND  PREPARATION  OF  SEED  BED 

On  this  plot   (No.  2,  photographed  in  1911)   the  ground  was  plowed,  a  seed  bed 
prepared,  and  the  weeds  kept  down  by  scraping  with  a  hoe. 

cultivation  was  given  after  planting.  The  weeds  were  kept  down  in  the 
same  way  as  on  Plot  1. 

Plot  3S  (Plot  3  until  1911)  (Fig.  5)  was  plowed  in  the  spring  and 
a  good  seed  bed  prepared,  but  after  planting  the  corn,  weeds  were 
allowed  to  grow. 

Plot  3N  was  plowed  and  a  seed  bed  prepared;  weeds  were  allowed 
to  grow  as  in  3S,  but  the  plot  was  irrigated  as  often  as  necessary  to  keep 
the  soil  in  a  moist  condition. 

Plot  4  (Fig.  6)  was  treated  the  same  as  Plot  2  except  that  the  corn 
was  given  three  shallow  cultivations  with  the  three-shovel  cultivator 
previous  to  1912  and  with  the  surface  cultivator  after  that  time.  Any 
weeds  that  escaped  the  cultivator  were  pulled  or  cut  out  with  a  hoe. 

Plot  5  (Fig.  7)  was  treated  the  same  as  Plot  4  except  that  the  crop 
was  irrigated  whenever  it  seemed  necessary. 


186 


BULLETIN  No.  259 


[March, 


Plot  6  (Fig.  8)  was  treated  similarly  to  Plot  5  except  that  2  tons 
of  rock  phosphate  and  80  tons  of  manure  per  acre  were  applied  once  in 
each  rotation  before  the  second  crop  of  corn. 

DISCUSSION  OF  RESULTS 

In  Table  3,  the  yield  of  the  cultivated  plot,  No.  4,  is  taken  as  the 
standard  for  computing  the  relative  yields  shown  in  the  last  three 
columns.  On  Plot  1,  without  plowing  or  the  preparation  of  a  seed  bed 
in  any  way  the  average  yield  for  nine  years  was  35.2  bushels  an  acre, 
or  81.3  percent  of  that  of  the  standard  cultivated  plot,  No.  4.  In  com- 
parison with  this,  on  Plot  2,  where  a  good  seed  bed  had  been  prepared 
and  the  weeds  kept  down,  the  percentage  yield  was  112.9;  while  the 
average  actual  yield  for  the  nine  years  was  48.9  bushels,  or  an  increase 
of  13.7  bushels  an  acre  over  Plot  1.  This  increase  presumably  repre- 
sents the  value  of  seed-bed  preparation.  The  lowest  yield  on  Plot  2 
was  33  bushels  in  1908  and  the  highest,  75.5  bushels  in  1912.  At  the 
time  these  results  were  secured  it  seemed  scarcely  possible  that  so  high 


FIG.  5. — UNMOLESTED  WEED  GROWTH  BADLY  STUNTED  THE  GROWTH  OF  CORN 

This  plot  (No.  3S,  photographed  in  1911)  was  undisturbed  after  planting.  In  spite 
of  previous  plowing  and  seed-bed  preparation,  the  resultant  growth  of  corn  was  very 
poor  and  the  yields  appreciably  lower  than  might  be  expected  from  the  growth  shown. 


1925] 


THE  CULTIVATION  OF  CORN 


187 


a  yield  could  be  produced  without  cultivation.  It  will  be  noticed  that 
Plot  2,  uncultivated,  gave  larger  yields  four  out  of  the  nine  years  than 
Plot  5,  the  cultivated  and  irrigated  plot,  and  that  the  average  for  Plot  2 
was  5.6  bushels  larger  than  for  the  standard  cultivated  plot,  No.  4. 

The  treatment  on  Plot  3  was  for  the  purpose  of  determining  the 
effect  of  weeds  on  the  corn  crop.  It  will  be  noticed  that  the  average 
yield  of  Plot  3S  was  only  17.1  percent  of  that  of  the  cultivated  plot; 
however,  the  actual  yields  varied  from  0  to  16  bushels.  The  results  on. 
this  plot  certainly  make  it  very  evident  that  corn  cannot  thrive  with 
weeds. 

In  order  to  determine  whether  it  was  a  lack  of  moisture  that  pro- 
duced the  low  yields  where  weeds  and  corn  were  grown  together,  Plot  3 
was  divided  in  1911,  and  the  north  half  was  irrigated  often  enough  to 
keep  the  soil  abundantly  supplied  with  moisture.  The  effect  was  quite 
noticeable  both  on  the  corn  and  the  weeds,  but  as  an  average  of  five 
years  the  yield  of  corn  was  increased  only  2.5  bushels  an  acre.  It  must 
therefore  appear  that  the  injury  done  by  weeds  is  not  due  so  much  to 
the  moisture  they  take  out  of  the  soil  as  to  some  other  cause  or  causes. 


FIG.  6. — WEED  CONTROL  BY  MEANS  OF  MODERATE  CULTIVATION  INSURED 
A  MORE  SATISFACTORY  GROWTH 

This  plot  (No.  4,  photographed  in  1911)  was  plowed,  a  seed  bed  prepared,  and  the 
corn  cultivated  three  times.  Compare  with  Figs.  4  and  5. 


188 


BULLETIN  No.  259 


[March, 


It  would  be  well  to  compare  very  carefully  Plot  4  with  Plots  2 
and  5.  Plot  2,  uncultivated,  produced  5.6  bushels  more  corn  per  acre 
than  Plot  4  with  standard  cultivation;  but  the  fact  should  be  empha- 


FIG.  7. — IRRIGATION  GAVE  A  SOMEWHAT  INCREASED  GROWTH 

Irrigation  on  this  plot  (No.  5,  photographed  in  1911)  in  addition  to  plowing,  seed- 
bed preparation,  and  cultivation,  gave  better  growth  but  not  an  economic  increase 
in  yield. 


sized  that  to  obtain  such  a  result  the  weeds  must  be  kept  down.  Plot  5, 
cultivated  and  supplied  with  all  the  moisture  that  was  necessary,  pro- 
duced as  an  average  of  nine  years  only  1.3  bushels  more  than  the 
uncultivated,  unirrigated  plot  where  weeds  were  kept  down.  Irrigation 
gave  an  increase  every  year  but  two.  These  exceptions  were  in  1912 
and  1915,  when  only  a  small  amount  of  water  was  used.  There  is  no 
doubt  that  the  one  irrigation  in  1912,  which  was  followed  within  a  few 
hours  by  a  heavy  rain,  did  no  good  and  even  may  have  damaged  the 
crop  to  some  extent. 

The  fertilizer  treatment  for  Plot  6  was  accidentally  omitted  for  the 
1909  crop  of  second-year  corn;  for  this  reason,  the  yield  for  that  year, 
as  given  in  Table  3,  is  for  first-year  corn  only,  and  is  not  included  in  the 
averages.  In  1914  a  storm  damaged  the  crop  badly,  especially  on  the 
fertilized  plot,  where  the  growth  was  particularly  heavy.  The  increase 


1925] 


THE  CULTIVATION  OF  CORN 


189 


for  fertilization  as  an  average  of  eight  years  was  18.3  bushels  an  acre, 
as  shown  by  comparing  the  yields  on  Plots  5  and  6  (Table  3).  It  should 
be  noted  that  the  fertilized  plot  received  an  excessive  amount  of  manure 


FIG.  8. — FERTILIZATION  PRODUCED  GREATER  GROWTH  OF  CORN 

This  plot  (No.  6,  photographed  in  1911)  was  plowed,  prepared,  cultivated,  and 
irrigated  in  a  way  similar  to  Plot  7,  but  in  addition  received  liberal  applications  of  rock 
phosphate  and  manure.  The  fertilizer  treatment,  however,  was  so  excessive  that  the 
increased  yield  does  not  represent  an  economic  gain. 

and  rock  phosphate,  and  that  the  increased  yield  on  this  plot  is  no  indi- 
cation of  the  value  of  rational  fertilizer  treatment  on  this  soil. 

The  fact  that  the  uncultivated  corn  produced  so  well  in  comparison 
with  the  cultivated,  also  with  the  cultivated  and  irrigated,  shows  that 
cultivation  for  conservation  of  moisture  is  decidedly  a  secondary  con- 
sideration in  this  climate  on  Brown  Silt  Loam.  On  Plot  2  the  crop 
could  use  all  the  plowed  soil  as  a  feeding  ground,  while  on  Plots  4,  5, 
and  6  probably  half  the  plowed  soil  was  so  disturbed  by  cultivation 
that  the  roots  of  the  corn  were  either  injured  or  could  not  develop  in 
the  stirred  portion  because  of  its  dry,  loose  character.  This  was  espe- 
cially true  on  Plot  4  during  dry  seasons.  As  a  result,  the  nutrients  in 
the  stirred  soil  were  of  little  benefit  to  the  crop;  the  logical  conclusion  is 
that  the  cultivated  soil  is  of  much  greater  value  for  the  plant  nutrients 
it  contains  than  for  the  moisture  it  may  conserve. 


190 


BULLETIN  No.  259 


to 


u 


/      • 

O   « 

5    fe 

<    a 

3   <» 
7  13 

S-S 


!?-* 

>s*^   •*-* 

r-~ 

"j 

f> 

o 

CO 

0s-  o 

oo 

CO 

— 

CO 

§ 

2 

i-     • 

to 

^ 

oo 

oo 

vo 

X  >• 

T*       a 

VO 

si 

to 

VC 

es 

£ 

O 

oo 

VO 

O 

CO 

CS   * 

co 

oo 

3 

co 

^ 

"f 

ON 

O 

O 

0 

0 

CO 

o 

0 

o 

-0 

vo 

ON 

o' 

0 

o 

CS  O 

2 

cs 

oo 

vo 

VO 

Tt-C-J 

, 

ON 

CS 

to 

•<f 

O    -H 

CS 

CS 

10    Tf 

VO 

rt 

CS 

_ 

^ 

ON  ^0 

VO 

ON 

CO 

CS 

oo 

VO  -t- 

CS 

CS 

CS-H 

CO 

CD 

o, 

h 

U 

"7^ 

O 

CO 

-C 

^i 

_c 

C 

TJ 
CD 

60 

O 

r= 

C 

^ 

{^ 

'EL 

a, 

^<LJ 

U 
CO 

u 

CO 

1 

c 

c" 
o 

*"O 

60 

*4J 

*p. 

-C 

U 

o 

> 

C8 

C 

£ 

^ 

'fi 

*4J 

O 

c" 

CD 

O 

9 
U 

C 
CD 

£ 

O. 

CD 

J4 

cs 
> 

"cS 
CO 

"x 

C8 

C 

V 

gd 

C 

of 
U 

H 

01 

T3 
U 

i 

O 
O 

1 

"3 

_0 

'•3 
_o 

cultivated, 

d  prepared, 
loe  

1 

OS 

— 
K 

cu 

d  prepared. 

•cT 
U 

m 

O. 

i 

a 
-a 

Ui 

qj  ^—  ^ 

^ 

CD 

O 

*^  "C 

•-Q 

^Q 

„ 

"^  ^ 

-a 

~O 

f-—  • 

T3 

CD 

"I  <» 

CD 
CD 

CO 

CD 
CD 

CD 
CD 
CO 

o 

13    c 

Tf 

T? 

T? 

O< 

CD'" 

u 

CJ 

CD 

O 

_o 

o 

O 

O 

£ 

OH 

OH 

OH 

OH 

_o  0° 

- 

cs 

CO 

* 

-, 

II" 


-.     p 

Jl 


o 

o 


3 

5 

CS  VO  OO  -H 

VO  OO  ON  CO 

CO  ^f  ^O  CO 

ON 
VO 

J 
P 

ON  ^0  oo  cs 

n  ~  —  -~. 

o 
cs 

o 

•<f  t^-  O  ON 

vo  oo  ^f  oo 

CS  CS  -^ 

cs 

8 

-H    Tf    OO   VO 

O  »o  O  oo 

CS          TjH  CO 

cs 

vo 

cs 

fr 

C/5 

O  co  to  oo 
oo  to  vo  to 

vo  co  -*1  co 

VO 

60 

3 

co  r»  vo  to 

to  00  Tf  ^ 

0 

"3 
1—, 

Tf    ^H    ^H   VO 

OO  ^  ^*  ^^ 

00 

cs 

U 

3 

1—4 

ON  to  oo  Tf 

OO  O  'f  <-> 
CO  OO  —  i  -H 

vo 
CO 

CS 

s 

OO  O  CS 
CS  C4  CO  -H 

^H  CO  CS 

o 

—  *  CS  O  VO 

cs  •*  r~  co 

vo  to  CO  CO 

vo 

C 

8  to  co  vo 
"*«  •*  co 

cs  •*  cs  co 

vo 
to 

J& 

CD 

ON  ON  to  CS 

—  0000 
CSCO  >-i  CO 

to 
cs' 

C 

CS 

O  to  oo  O 

Tf    00    -H    CO 

—  —  dcs 

CO 

ON 

CO 

i-"'  CS  CO  •* 
ON  ON  ON  ON 

Average  

1925~\  THE  CULTIVATION  OF  CORN  191 

EXPERIMENTS  IN  SOUTHERN  ILLINOIS 

A  series  of  experiments  was  conducted  at  the  Fairfield  experiment 
field  in  Wayne  county,  on  Gray  Silt  Loam  On  Tight  Clay,  the  common 
prairie  soil  of  southern  Illinois,  to  ascertain  the  relative  value  of  cultiva- 
tion and  thoro  seed-bed  preparation  on  that  type  of  soil. 

This  experiment  in  general  was  similar  to  the  one  begun  at  Urbana 
in  1907  except  that  irrigation  was  not  practiced.  The  plots,  twelve  in 
number  and  one-tenth  of  an  acre  in  size,  were  arranged  in  two  series, 
one  of  which  was  cropped  to  corn  in  1908  when  the  experiment  was 
started.  According  to  the  records,  the  1908  corn  yields  are  unreliable, 
due  to  damage  by  livestock,  and  are  therefore  omitted.  No  corn  was 
grown  on  either  series  in  the  years  1909  and  1910.  The  original  four- 
year  rotation  of  corn,  cowpeas,  wheat,  and  clover  was  changed  in  1912 
to  a  two-year  rotation  of  corn  and  soybeans.  The  tillage  and  fertilizer 
treatments  of  the  individual  plots  are  explained  in  Table  7.  Table  8 
shows  the  monthly  rainfall  during  the  years  for  which  the  corn  yields 
are  reported. 

The  value  of  seed-bed  preparation  is  shown  by  comparing  the  corn 
yields  on  Plot  1,  which  received  no  preparation,  with  those  on  Plot  2, 
which  was  thoroly  prepared  prior  to  planting.  This  comparison  shows 
that  on  Gray  Silt  Loam  On  Tight  Clay,  seed-bed  preparation  trebled  the 
yield.  On  Brown  Silt  Loam  at  Urbana  it  resulted  in  an  increase  of 
almost  40  percent.  Expressed  in  actual  yield,  the  increase  at  Fairfield 
was  12.9  bushels  an  acre,  and  at  Urbana,  13.7  bushels. 

Where  the  seed  bed  had  been  prepared,  cultivation  resulted  in  an 
apparent  decrease  of  2.6  bushels  an  acre,  as  a  four-year  average  (com- 
pare Plots  2  and  4).  For  the  first  two  years  the  decrease  was  5.8  bushels 
an  acre  a  year. 

The  fertilized  plot,  No.  5,  yielded  64.3  percent  more  than  the 
standard  cultivated  plot,  No.  4,  an  increase  of  10.8  bushels  an  acre 
yearly.  This,  however,  does  not  represent  a  profitable  gain  because  of 
the  cost  of  the  excessive  fertilizer  treatment. 

The  Fairfield  results,  while  failing  to  indicate  the  relative  merits 
of  scraping  compared  with  ordinary  cultivation,  show  rather  clearly 
the  necessity  of  seed-bed  preparation  on  this  type  of  soil.  However, 
the  limited  amount  of  data  furnished  by  the  present  experiment  does 
not  warrant  the  drawing  of  any  definite  conclusions. 

RECENT  EXPERIMENTS  AT  URBANA 

The  most  recent  experiments  on  corn  cultivation  at  this  Station 
were  conducted  from  1916  to  1921  inclusive,  on  the  Roland  farm, 
Urbana,  which  is  now  a  part  of  the  Stadium  field.  The  purpose  of  this 
series  of  experiments  was  to  study  the  effect  upon  corn  yield  of  weeds 
growing  unmolested;  of  surface  scraping  to  eradicate  weeds  without 
the  formation  of  a  mulch;  and  of  shallow  cultivation  with  blade  or 


192  BULLETIN  No.  259  [March, 

shovel  cultivator.  These  studies  were  made  on  both  fertilized  and  un- 
fertilized plots,  arranged  in  four  series  of  six  plots  each.  The  size  of 
the  individual  plots  was  y6-^  of  an  acre. 

The  soil  on  which  these  experiments  were  conducted  is  the 
morainal  Brown  Silt  Loam,  the  same  type  of  soil  used  for  the  series  of 
cultivation  experiments  in  progress  from  1907  to  1915.  A  four-year 
rotation  of  corn,  corn,  oats,  and  sweet  clover  was  practiced,  with  soy- 
beans as  a  substitute  crop  when  the  clover  failed  in  1916,  1917,  and 
1919.  All  cornstalks  and  residues  were  removed  from  those  plots 
which  received  no  treatments  of  manure,  rock  phosphate,  or  limestone. 
All  corn  plots  were  disked,  plowed,  prepared,  and  planted  in  the  same 
manner. 

TREATMENT  OF  PLOTS 

On  Plots  1  and  2  the  weeds  were  allowed  to  grow.  On  Plots  3  and 
4  the  weeds  were  kept  down  by  scraping  with  a  sharp  hoe  without 
forming  a  mulch.  On  Plots  5  and  6  the  corn  was  given  three  or  four 
shallow  cultivations,  a  blade  cultivator  being  used  on  the  north  half 
and  a  3-shovel  cultivator  on  the  south  half  of  the  plots.  The  average 
depth  of  the  cultivations  was  about  1  to  1%  inches  for  "blades"  and 
2  to  3  inches  for  "shovels." 

With  reference  to  the  fertility  treatments,  Plots  1,  3,  and  5  served 
as  checks  in  that  they  received  no  residues,  manure,  phosphate,  or 
limestone.  Plots  2,  4,  and  6  received  manure  in  proportion  to  the  crops 
produced,  also  1  ton  of  rock  phosphate  and  2  tons  of  limestone  per 
acre  once  in  a  rotation.  Manure,  equal  in  weight  to  all  corn  (grain), 
oats  (grain  and  straw),  and  clover  (hay  and  seed)  removed  from  each 
plot,  was  returned  to  that  plot  in  the  spring  preceding  second-year 
corn.  Applications  of  phosphate  and  limestone  were  made  in  the  fall 
or  early  winter  previous  to  the  1916  and  1920  crops. 

DISCUSSION  OF  RESULTS 

A  careful  study  of  the  data  in  Tables  9,  10,  and  11,  reporting 
yields  and  rainfall,  fails  to  show  any  definite  relation,  similar  to  that 
illustrated  in  Fig.  2,  between  the  total  rainfall  during  the  growing 
period  and  the  cultivation  needs  of  corn  in  seasons  of  deficient  rainfall. 

In  Table  9  the  yield  of  the  shovel-cultivated  plot  is  taken  as  100 
percent,  or  the  standard  for  computing  the  relative  yields  of  the  other 
plots.  It  should  be  noted  that  since  the  actual  yields  of  the  standard 
plots  (the  cultivated  plots  Nos.  SS  and  6S),  are  widely  different,  the 
percentage  values  for  the  yield  of  corn  on  the  unfertilized  plots  are  not 
directly  comparable  with  those  of  the  fertilized  plots. 

The  corn  yields,  as  shown  by  the  six-year  averages,  were  always 
higher  on  the  fertilized  than  on  the  corresponding  unfertilized  plots. 
The  fertility  treatment  gave  an  apparent  increase  of  4.6  bushels  of 


1925} 


THE  CULTIVATION  OF  CORN 


193 


•z 
•i 
O 
et 

pq 

Q 


D  B 


N      > 


K     « 
S-S 


U 
o\ 


T3 

CJ                     .J 

•  WO 

••* 

VO  O 

°   >             li' 

i35^2 

•o 

:S 

r~-o 

o\o 

S3  V5,     j 

>-j;          j, 

<|         ^ 

JC             i—  \ 
to             |J 

t^    • 

ro     • 

co  • 

S  : 

I--O 

cod 

00 

>' 

rt 

O  \0 

co  vo 

0-H 

i-l  >0 

>. 

VO 

r^  ^ 

co  wo 

wo  wo 

CO  — 
wo  wo 

oo  CT\ 

wo  wo 

_ 

WO  OO 

-H  wo 

•*•<*< 

o\oo 

CT\ 

•*-H 
l-H   tM 

con 

wo  wo 

\O  CO 

WO  wo 

rf  wo 

VO  \O 

s 

vor^ 

TfCO 

•*tN 

o  o\ 

0\ 

O\O 

so  —  i 
wo  SO 

—,0 
wo  wo 

OI^ 

SO  SO 

Ov 

OxO 

o  ^o 

tN  wo 

•*o 

CT\ 

fS  Tf 

VO  1-1 
wo  \o 

i—  i  WO 

\O  wo 

-Hf-. 

SO  wo 

oo 
o\ 

C>  oo 

—  •* 

r-^  •* 

Os  tS 

10  ^o 

<N  -H 

\O  wo 
wo  wo 

•*  CN 

SO  SO 

r^ 

c\ 

i—  (  ro 

CO  wo 
-^  CS 

!-•    CO 

\£>  10 

SO  vo 

r^\o 

do\ 

SO  wo 

i—  1  WO 

Tj^r~! 

so  vo 

VO 

IO  wo 

\o  oo 

O  vo 

Tj<  WO 

OS 

oc  O\ 
C4<N 

CN  CN 

coco 

CO  vo 
CO  CO 

Unfertilized 
Fertilized 

Unfertilized 
Fertilized 

Unfertilized 
Unfertilized 

Fertilized 
Fertilized 

u 

E 

rt 
g 

H 

£  * 

2  £ 

60  bC 

22 

T3-d 

gg 

_o_o 

"CB  "rt 

CO     CO 

-c-o 

U    --J 
U     OJ 

££ 

88 

JS  J5 

•£  -^ 

'?'? 

-O-T3 
u  u 

a  o. 

ca  ca 
u  1-1 

o  u 

COW 

Cultivated  —  blades  .... 
Cultivated  —  shovels  

Cultivated  —  blades  .... 
Cultivated  —  shovels  

o  6 

tt 

—i  CN 

CO  Tf 

Zc/5 
WO  wo 

£</3 
so  SO 

194 


BULLETIN  No.  259 


[March, 


5 

£ 


•/      '— 

§^  a 


Qsfc 


H 

T 

o 


8 

(X) 

O 

2 

CO 

VO 
to 

O 

CO 
»o 

to 

oo 

>o 
ft 

1 

r-o4 

^t- 

t-ON 

tot- 

OO  •—  I 

co  oo 

co  oo 

co  VO 

sot- 

COON 

vo  O\ 

t-  co 

OO  f—  - 
to  Tf 

to  Tf 

SO  to 

co  ft 
vo  to 

t-oi 

01  Tf 

CO  00 

oo  cs 

r-  —i 

t-0 

<*<« 

~f, 

O  oo 

COO 
04  O4 

O  *^~> 

so  -^ 

co  co 
tO  to 

to  t— 

so  •* 

to  .-i 

so  "f 

CO  vo 

r^  wt 

0 

—H   ,-1 

^0 

^^ 

VOON 

ON  oo 

04  0< 

^so 

TfTt- 

ONO 

£2 

SO  SO 
to  *o 

to  so 

—i  O 
to  to 

** 

O  ON 

-H    T*. 

I—*  vo 

ON 

••H  SO 

covo 

OS  ^H 

so  ft 

*>t- 

covo 

01  vo 

•f  vo 

2 

Tf~ 

•<*<  co 

%Z 

ON  co 
so  *^"> 

oo  co 
so  ^o 

co  r— 

so  ^ 

SO  to 

vo  to 

oo 

.-ISO 

sO  ON 

oo  so 

O  oo 

OO  SO 

^t- 

^H   CO 

to  vo 

2 

co 

OO 

so  ft 

to  ON 
so  ""> 

to  so 
so  •* 

SO  CO 

to  to 

VO  co 
so  SO 

so  vo 

^ 

04  ON 

TfCS 

CO  ON 

I-  ON 

co  O 

04  ON 

—I  r-t 

r-HOO 

2 

CO  04 

so  -"f 

04  04 

to  ^O 

so  SO 

»y^  ^ 

*O  V*O 

so  to 

sO  04 
so  to 

oo  O 
so  so 

oo  so 
so  vo 

vo 

~0 

CO  O 

•-Th 

Tf  CN 

<**> 

ON  co 

VO-H 

cot- 

2 

CO  ?S 

>-i  OO 
CO  04 

so  I— 
cool 

OI  04 
•*•  04 

^5  \O 
Tt*  CN 

to  t— 

S,  a 
o 

il 

M 

C    c! 

si 

8  o 

ii 

ii 

II 

11 

01  T3 

£  (N 

1-5" 

to  T3 

5% 

co  T3 

<->  04 

II 

Unfertilized 

Fertilized.  .  . 

Unfertilized 

Fertilized  .  .  . 

Unfertilized 

I 

c 
D 

Fertilized.  .  . 

Fertilized.  .  . 

Treatment 

Weeds  allowed  to  grow  

W7eeds  allowed  to  grow  

u 

o 

cL 

as 

o 

'5 

u 
Oi 

rt 

0 
C^) 

Cultivated  —  blades  

Cultivated  —  shovels  

Cultivated  —  blades  

Cultivated  —  shovels  

4-1        • 

SZ 

- 

04 

n 

« 

to 

n 

"0 

fc 

sO 

C/} 
SO 

1925] 


THE  CULTIVATION  OF  CORN 


195 


3 

-*  CO  »0  >0  ON  SO 
t~-  CS  Ol  CS  CS  VO 

to 

CS 

H 

O\  cs  ro  to  o  »-i 
cs  o  •*  «  «s  •* 

>0 

CO 

u 

>y 

O\  O  ON  fN  —  <  oo 
ON  ^O  Os  *—  '  oo  ON 

ON 

U 

^H      CO      (N  -H 

"-1 

o 

co  oo  co  r^  Os  *•"' 
ON  ^r^  co  CS  ON 

CO 

cs 

fc 

^H      _"._-)- 

cs 

4-j 
<j 

XO  •«*<  CS  ON  CS  co 
CS  CO  oo  w.  O  CS 

00 
00 

O 

CS  CS  CS  10  CS  CS 

es 

a 

ON  —  «  r->  r^  ON  -^f 
vo  o  ON  -<f  r»  >o 

Tf 

es 

C/5 

CS  CS  •*  CS  ^  w-i 

CO 

ti 

3 

vo  O  >o  10  oo  \o 
^*  oo  '—i  oo  ^5  co 

cs 

so 

< 

i-<  CO  «o  CO  CO  •* 

CO 

_>» 

co  co  >o  NO  ON  •*> 

»o 

CO 

1—  V 

CS  CS  CS  CO  CS. 

cs 

1 

oo  >o  ON  O  •*  oo 
oo  Tf  so  ON  ON  vo 

8 

•—  » 

co  so  <o  so   <-i 

Tf 

>. 

CS 

O  >o  Tf  ON  oo  so 

r^  >o  so  cs  t^  cs 

•* 

»0 

s 

IO  Tf  Tf  CO  CO  *O 

"*• 

a. 

OO  CN  Tf  «O  -H  10 

es  so  oo  j^-r^  cs 

ON 

< 

«—  i  co  so   10  «o 

CO 

iZ 

CO 

•*"  corses  o  cs 

T—  1  Tf  >O  1—  1  Tf  OO 

5 

s 

*-H  T^(  v—  1  Tt<  CO  *O 

CO 

j£ 

co  >o  so  cs  >o  ON 
so  ^  oo  ON  Tf  -^< 

1^ 

ON 

£ 

*"  ^ 

c 

cs  t^-  --t1  —  co  o 

O  O  t^-  CS  OO  SO 

ON 

1—  > 

SO  rt  rt          M 

1-1 

V 

{* 

SO  t^  OO  ON  O  —  < 
«  —  <  ^-c  •—  i  CS  CS 

ON  ON  ON  Os  ON  ON 

^ 

<r 

196  BULLETIN  No.  259 

corn  per  acre  on  the  weed  plot,  No.  2;  2.3  bushels  on  the  scraped  plot, 
No.  4;  5.1  bushels  on  the  "blade"  cultivated  plot,  No.  6N;  and  8.4 
bushels  on  the  "shovel"  cultivated  plot,  No.  6S.  These  increases  are 
probably  too  small  to  show  an  economic  gain  for  the  fertilization  used. 

The  removal  of  weeds  by  scraping  with  a  hoe  instead  of  by  culti- 
vation increased  the  yield  46.3  bushels  an  acre  on  the  unfertilized 
plot,  No.  3,  and  44  bushels  on  the  fertilized  plot,  No.  4.  The  average 
yields  of  the  unfertilized  plots  that  were  scraped  and  cultivated  (Plots 
3  and  5)  show  no  significant  differences,  thus  indicating  that  the  great- 
est value  of  cultivation  with  either  blades  or  shovels  was  to  eradicate 
weeds. 

When  fertilized,  the  cultivated  plots  produced  an  average  of  2.5 
to  3.9  bushels  an  acre  more  than  the  scraped  plots.  While  no  great 
importance  can  be  attached  to  these  small  differences,  they  might  sug- 
gest the  possibility  that  the  corn  plant,  when  grown  on  a  heavily 
fertilized  soil,  is  less  dependent  upon  the  natural  fertility  of  the  surface 
soil  or  perhaps  has  greater  power  of  recovery  from  root  injury  caused 
by  cultivation. 

NOTE 

This  bulletin  includes  material  published  in  Bulletin  181  of  this  Station  (1915) 
entitled  "Soil  Moisture  and  Tillage  for  Corn,"  by  J.  G.  Mosier  and  A.  F.  Gustafson. 
Its  purpose  is  to  bring  the  discussion  on  corn  cultivation  up  to  date  and  to  include 
the  final  results,  the  work  on  this  problem  now  having  been  discontinued. 

The  experimental  work  on  corn  cultivation  at  the  Illinois  Station,  as  herein 
reported,  falls  into  three  periods:  first,  early  experiments  at  Urbana  begun  in  1888  by 
Morrow  and  Hunt  and  terminated  in  1893;  second,  later  experiments  begun  at  Urbana 
in  1906  and  at  Fairfield  in  1908  by  Mosier  and  terminated  in  1915;  third,  experiments 
begun  in  1915  on  the  Roland  farm,  Urbana,  by  Mosier  and  Gustafson,  and  terminated 
in  1922  because  of  the  location  of  the  Memorial  Stadium  on  this  field. 

The  data  secured  during  the  first  period  of  experimentation  are  reprinted  from 
Bulletin  181;  the  data  obtained  in  the  second  period  have  been  corrected,  completed,  and 
rearranged  in  part;  while  the  data  secured  since  Bulletin  181  was  published,  or  for  the 
third  period,  are  presented  for  the  first  time.  It  should  be  explained  that  the  soil  tem- 
perature and  moisture  data  found  in  Bulletin  181  are  omitted  because  subsequent  work 
has  shown  them  to  be  of  questionable  value;  the  number  of  determinations  of  temper- 
ature and  moisture  in  the  individual  plots  was  insufficient  to  give  reliable  averages. 

This  material  represents  the  contributions  of  a  number  of  present  and  former  mem- 
bers of  the  Agronomy  Department.  Special  recognition  should  be  given  the  late  Pro- 
fessor J.  G.  Mosier  and  Professor  A.  F.  Gustafson,  mentioned  above,  Mr.  F.  A. 
Fisher,  now  Farm  Adviser  of  Wabash  county,  and  Dr.  R.  S.  Smith,  Associate  Chief 
in  Soil  Physics. 


UNIVERSITY  OF  ILLINOIS-URBANA 


